Palladium‐ or ruthenium‐catalyzed synthesis of 2‐phenylindoles

Abstract Allyl α‐phenyl‐2‐aminophenethyl carbonates undergo a smooth decarboxylation‐dehydrogenation reaction to afford 2‐phenylindole derivatives in acetonitrile at 80° in the presence of palladium complex as catalyst. In the reaction, the ruthenium hydride complex showed more effective catalytic activities. 2‐Phenylindoles were also prepared from the corresponding α‐phenyl‐2‐aminophenethylalcohols and allyl methyl carbonate by ruthenium‐catalyzed cyclization.